﻿// bsn ModuleStore database versioning
// -----------------------------------
// 
// Copyright 2010 by Arsène von Wyss - avw@gmx.ch
// 
// Development has been supported by Sirius Technologies AG, Basel
// 
// Source:
// 
// https://bsn-modulestore.googlecode.com/hg/
// 
// License:
// 
// The library is distributed under the GNU Lesser General Public License:
// http://www.gnu.org/licenses/lgpl.html
// 
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// 
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Lesser General Public License for more details.
// 
// You should have received a copy of the GNU Lesser General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

using System;
using System.Collections.Generic;

namespace bsn.ModuleStore.Sql.Script {
	internal class CommonTableExpressionScope {
		private readonly HashSet<string> names = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
		private readonly CommonTableExpressionScope parent;

		public CommonTableExpressionScope(CommonTableExpressionScope parent) {
			this.parent = parent;
		}

		public void AddName(string name) {
			names.Add(name);
		}

		public bool ContainsName(string name) {
			if (names.Contains(name)) {
				return true;
			}
			if (parent != null) {
				return parent.ContainsName(name);
			}
			return false;
		}
	}
}
